diff options
Diffstat (limited to 'arch/powerpc/platforms/pseries/dtl.c')
-rw-r--r-- | arch/powerpc/platforms/pseries/dtl.c | 38 |
1 files changed, 13 insertions, 25 deletions
diff --git a/arch/powerpc/platforms/pseries/dtl.c b/arch/powerpc/platforms/pseries/dtl.c index ef6595153642..2b87480f2837 100644 --- a/arch/powerpc/platforms/pseries/dtl.c +++ b/arch/powerpc/platforms/pseries/dtl.c @@ -1,23 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* * Virtual Processor Dispatch Trace Log * * (C) Copyright IBM Corporation 2009 * * Author: Jeremy Kerr <jk@ozlabs.org> - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2, or (at your option) - * any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include <linux/slab.h> @@ -40,13 +27,7 @@ struct dtl { }; static DEFINE_PER_CPU(struct dtl, cpu_dtl); -/* - * Dispatch trace log event mask: - * 0x7: 0x1: voluntary virtual processor waits - * 0x2: time-slice preempts - * 0x4: virtual partition memory page faults - */ -static u8 dtl_event_mask = 0x7; +static u8 dtl_event_mask = DTL_LOG_ALL; /* @@ -61,7 +42,6 @@ struct dtl_ring { struct dtl_entry *write_ptr; struct dtl_entry *buf; struct dtl_entry *buf_end; - u8 saved_dtl_mask; }; static DEFINE_PER_CPU(struct dtl_ring, dtl_rings); @@ -111,7 +91,6 @@ static int dtl_start(struct dtl *dtl) dtlr->write_ptr = dtl->buf; /* enable event logging */ - dtlr->saved_dtl_mask = lppaca_of(dtl->cpu).dtl_enable_mask; lppaca_of(dtl->cpu).dtl_enable_mask |= dtl_event_mask; dtl_consumer = consume_dtle; @@ -129,7 +108,7 @@ static void dtl_stop(struct dtl *dtl) dtlr->buf = NULL; /* restore dtl_enable_mask */ - lppaca_of(dtl->cpu).dtl_enable_mask = dtlr->saved_dtl_mask; + lppaca_of(dtl->cpu).dtl_enable_mask = DTL_LOG_PREEMPT; if (atomic_dec_and_test(&dtl_count)) dtl_consumer = NULL; @@ -201,11 +180,16 @@ static int dtl_enable(struct dtl *dtl) if (dtl->buf) return -EBUSY; + /* ensure there are no other conflicting dtl users */ + if (!read_trylock(&dtl_access_lock)) + return -EBUSY; + n_entries = dtl_buf_entries; buf = kmem_cache_alloc_node(dtl_cache, GFP_KERNEL, cpu_to_node(dtl->cpu)); if (!buf) { printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n", __func__, dtl->cpu); + read_unlock(&dtl_access_lock); return -ENOMEM; } @@ -222,8 +206,11 @@ static int dtl_enable(struct dtl *dtl) } spin_unlock(&dtl->lock); - if (rc) + if (rc) { + read_unlock(&dtl_access_lock); kmem_cache_free(dtl_cache, buf); + } + return rc; } @@ -235,6 +222,7 @@ static void dtl_disable(struct dtl *dtl) dtl->buf = NULL; dtl->buf_entries = 0; spin_unlock(&dtl->lock); + read_unlock(&dtl_access_lock); } /* file interface */ |